Safety switch means



y 1967 c. H. M FARLAND SAFETY swnrcn MEANS 2 Sheets-Sheet 1 Filed June1, 1965 INVENTOR.

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ucFARLANDZ M ATTORNEYS May 16, 1967 Filed June 1, 1965 C. H. M' FARLANDSAFETY SWITCH MEANS 2 Sheets-Sheet 2 TO BRUSH T0 FOOT SWITCH 75 TO FIELD10 FIELD Tl/O 72 may;

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INVENTOR. QHA LES Hty FARLA ATTORNEYS United States Patent Ofifice3,319,282 Patented May 16, 1967 3,319,282 SAFETY SWITCH MEANS Charles H.MacFarland, Rocky River, Ohio, assignor to The Scott & Fetzer Company,Cleveland, Ohio, a corporation of Ohio Filed June 1, 1965, Ser. No.460,198 4 Claims. (Cl. -319) ABSTRACT OF THE DISCLOSURE A safety switchfor a vacuum cleaner which includes switch elements responsive to theattachment of accessories to the vacuum cleaner to change the motorspeed of the vacuum cleaner according to the function of a particularaccessory attached to the cleaner. An interlock is provided to preventthe simultaneous operation of the switch elements.

This invention relates to suction cleaners and, more particularly, to asafety switch for suction cleaners that automatically varies the speedof the suction cleaner motor in response to different types ofattachments that are removably fixed to the body of the cleaner.

Many conventional suction cleaners employ a twospeed motor which iscontrolled by a manually operated switch. For cleaning rugs and carpets,a low speed is desired, since the carpet pile or rug tends to block thesuction end of the cleaner and may cause a high-speed motor to run hotbecause of the increased load on the fan. Moreover, if the beater brushis operated at a high speed on a carpet or rug, the suction cleanerwears the carpet pile too fast and the cleaner is difficult to push. Ahigh speed is desirable in applications where dusting attachments areconnected to the sweeper, since the ends of these attachments are spaceda considerable distance from the suction fan and a pressure drop occursalong the length of the hose from the dusting nozzle to the sweeperbody.

Frequently, the operator becomes confused as to the particular speedrecommended for a particular attachment. Suction cleaners have beendesigned, therefore, to include switches which are responsive to aparticular attachment. For example, in a patent to Smellie No.2,072,690, there is disclosed a suction cleaner having a two-speed motorwhich is operated in response to a switch. The switch, in turn, is atwo-position switch which is actuated to its first position only inresponse to a dusting attachment to thereby run the motor at arelatively high speed and is acuated to its second position only inresponse to a carpet cleaning nozzle to thereby run the motor at arelatively low speed. Prior art switches of the type shown in theSmellie patent control the motor speed by a field tap arrangement. Oneposition of such a switch cuts out a portion of the field winding of themotor to permit the motor to run at a higher speed because of thedecreased field resistance. The other position of such a switch connectsthe line across the entire field winding to reduce the motor speedbecause of the increased field resistance.

The conventional switches have met with limited commercial successbecause of the expense involved in field tap wiring systems. A farsimpler wiring arrangement for controlling the speed of a motor is toprovide a switch that will connect the field windings in series for lowspeed operations and that will connect the field windings in parallelfor high speed operations. Such a wiring arrangement in its simplestform, however, has not been employed since the field windings areshort-circuited and the current is applied directly through the armatureif the high speed and low speed switches are intentionally orinadvertently closed.

According to the present invention, however, a simple wiring arrangementand switch have been devised that will alternately connect the fieldwindings of a motor in series for low speed cleaning operations inresponse to low speed cleaning attachments and will connect the fieldwindings in parallel for high speed cleaning operations in response tothe provision of high speed cleaning attachments on the suction cleaner.The invention includes means to permit the alternate operation of thehigh speed and low speed switches, but prevents the simultaneousoperation of both switches.

It is an object of the present invention, therefore, to provide a safetyswitch for suction cleaners that will operate a motor at a low speed byconnecting the field windings of the motor in series and which willalternately connect the field windings of the motor in parallel tooperate the motor at a high speed.

It is a further object of the invention to provide an interlock betweenswitch plungers to prevent the simultaneous operation of such plungers.

The foregoing and various additional objects, features, and advantagesof the invention will become apparent and more fully understood from thefollowing detailed description, and from the accompanying drawings, inwhich:

FIG. 1 is a side elevation of the fan casing of a suction cleaner, aportion of the casing being broken away for clarity;

FIG. 2 is a front elevational view of the fan casing, the plane of theview being indicated by the line 2--2 in FIG. 1;

FIG. 3 is a side elevational view of a suction nozzle which may beattached to the fan casing;

FIG. 4 is a fragmentary, elevational view of the suc tion nozzle, theplane of the view being indicated by the line 44 in FIG. 3;

FIG. 5 is a fragmentary, elevational view of a hose attachment which maybe connected to the fan casing;

FIG. 6 is an elevational view of the hose attachment, the plane of theview being indicated by the line 66 in FIG. 5;

FIG. 7 is a partly schematic, sectional view of a safety switchaccording to this invention, the plane of the section being indicated bythe line 77 in FIG. 1;

FIG. 8 is a diagrammatic view of the electrical circuit of the cleaner;

FIG. 9 is a fragmentary view, partly in section, of a portion of thesafety switch;

FIG. 10 is a fragmentary view, partly in section, of a portion of thesafety switch showing one of the switch elements depressed; and

FIG. 11 is a fragmentary view, partly in section, of a portion of thesafety switch, showing the other switch element depressed.

Referring now to the drawings, and particularly to FIGS. 1 through 6, aconventional type vacuum cleaner is shown. The cleaner includes a fancasing 20 which has a vertical front wall 21 provided with a centralinlet opening 22. The fan casing includes a tangential outlet 23. A fan24 is mounted therein on a shaft 25 and the shaft 25 is driven by amotor 26. The motor 26 is mounted in a suitable housing 27 which isattached to the fan casing 20. The fan shaft 25 projects forwardlythrough the opening 22 and has a forward end portion 28 formed toprovide a belt pulley.

The fan casing 20 is mounted upon a suitable carriage 29 that isprovided with supporting wheels 30. A carpet or rug cleaning nozzle 31(FIG. 3) may be removably attached to the fan casing 20 and is providedwith a tubular portion 32 which receives the fan shaft 25 and which hasan end portion 33 that fits within the opening 22. The nozzle 31 hasslotted lugs 34 on the underside of the tubular portion 32 and theselugs engage a horizontal pin 35 that is carried by the fan casing. Afiange 36 is provided on the upper side of the nozzle 31, and the flange36 bears against the outer face of the front wall 21 and is locked inthis position by a clamping member 37 to secure the nozzle to the fancasing.

The nozzle 31 has a downwardly flared inlet portion 38 at its lower endand a brush 39 is rotatably mounted within the portion 38. The brush 39is driven by means of a belt (not shown) which is twisted to provide anupper loop engaging the pulley portion 28- of the shaft 25 and a lowerloop which extends around the brush 39. The upper loop may be connectedor disconnected from the pulley portion 28 by a belt lifter 40. Theoperation of such a belt lifter is conventional and is more fully setforth in my prior Patent No. 2,538,464.

The nozzle 31 is further provided with a downwardly extending finger 41.When the nozzle 31 is attached to the fan casing 20 in the mannerpreviously indicated, the finger 41 depresses a plunger 42 which isprovided on a safety switch 43. The safety switch 43 is mounted on thecarriage 29 by screws 44. As will hereinafter become apparent, thedepression of the plunger 42 by the finger 41 causes the motor 26 tooperate the fan 24 and the shaft 25 at a relatively low speed.

Referring now to FIGS. and 6, a fitting 45 is illustrated. A flexiblehose 46 is connected to one end of the fitting. The remote end of theflexible hose 46 may be provided with a suitable cleaning tool (notshown) for off-the-fioor cleaning operations, such as, for example,cleaning Venetian blinds or drapes. The fitting 45 is detachably securedto the fan casing 20 and includes an end portion 47 that fits within theopening 22. The fitting 45 has slotted lugs 48 on its underside and thelugs 48 engage the horizontal pin 35 carried by the fan casing. A flange49 is provided on the fitting 45 and the flange 49 is engaged by theclamping member 37 to secure the fitting to the wall 21.

The fitting 45 further includes a downwardly extending finger 50'. Whenthe fitting 45 is attached to the fan casing in the manner previouslyindicated, the finger 50 depresses a plunger 51 which is provided on thesafety switch 43. As will hereinafter become apparent, the depression ofthe plunger 51 by the finger 50 causes the motor 26 to operate the fan24 and shaft 25 at a relatively high speed.

Referring now to FIGS. 7 through 11, the plungers 42 and 51 are eachbiased upwardly by springs 52 and 53. The plunger 51 and the plunger 42are respectively provided with opposing side cavities or pockets 54 and55. A pin 56 extends between the plungers 42 and 51 and, when bothplungers are biased upwardly, the ends of the pin 56 partially projectinto each pocket 54 and 55 (FIG. 9). When the plunger 42 is depressed(FIG. the pin 56 is pushed out of the pocket 55 by a sloping upper face57 of the pocket 55. One end of the pin 56 is thereby freed fromconnection with the plunger 42 and the other end of the pin 56 is drivendeeper into the pocket 54. Similarly, when the plunger 51 is depressed(FIG. 11), the pin 56 is pushed out of the pocket 54 by a sloping upperface 58 of the pocket 54. One end of the pin 56 is thereby freed fromconnection with the plunger 51 and the other end of the pin 56 is drivendeeper into the pocket 55. When one of the plungers 42 and 51 isdepressed, the other plunger may not be depressed, since the travel ofthe pin 56 is limited by the flat side face of the depressed plunger.Moreover, the plungers 42 and 51 may not be depressed simultaneously,since the distance between the flat side faces of the plungers 42 and 51is less than the length of the pin 56.

When the plunger 42 is depressed, a contact 59 closes a circuit betweenfixed contacts 60 and 61. When the circuit is established through thecontacts 60 and 61, the field windings 62 and 63 of the motor 26 areconnected in series to the brushes 64 and 65 and the armature 66 of themotor .26, The motor 26 may be energized by a suitable foot switch 67which connects the motor 26 to a power line L L When the foot switch 67is closed, the motor 26 operates at a relatively low speed, since thefield resistance is relatively high when the fields are connected inseries. The actuation of the foot switch 67 also connects a floor light68 to the power line.

When the plunger 51 is depressed, an upper movable contact 70 on theplunger 51 establishes a circuit across a pair of fixed contacts 71 and72. Similarly, a lower movable contact 73 on the plunger 51 establishesa circuit across a pair of fixed contacts 74 and 75. When the circuit isestablished through the contacts 71, 72, 74 and '75, and the foot switch67 is closed, the field windings 62 and 63 are connected in parallelwith the brushes 64 and 65 and the armature 66 to run the motor 26 at arelatively high speed because of the lowered field resistance.

As was previously indicated, the pin 56 prevents the simultaneousoperation of the plungers 42 and 51. If both of the plungers wereoperated to close the contacts 71 and 72, 60 and 61, and 74 and 75, thefield 62 and 63 would be shorted and the line current would be applieddirectly to the brushes 64 and 65 and to the armature 66.

The invention is not restricted to the slavish imitation of each andevery one of the details described above, which have been set forthmerely by way of example with the intent of most clearly setting forththe teaching of the invention. Obviously, devices may be provided whichchange, eliminate, or add certain specific structural details withoutdeparting from the invention.

What is claimed is:

1. In a suction cleaner having a motor, a body portion, andinterchangeable attachments for cleaning operations requiring differentmotor speeds, the improvement comprising a safety switch having firstand second switch means, said first switch means being responsive to afirst linkage means which, in turn, is responsive to the connection ofone of the attachments to the body portion of the cleaner to run themotor at a relatively low speed, said second switch means beingresponsive to a second linkage means which, in turn, is responsive tothe connection of another attachment to the body portion of the cleanerto run the motor at a relatively high Speed, and means for preventingthe simultaneous operation of said first and second linkage means and,therefore, said first and second switch means.

2. In a suction cleaner having a motor, a body portion, andinterchangeable attachments for cleaning operations requiring differentmotor speeds, the improvement comprising a safety switch having firstand second plungers, said first plunger being responsive to theconnection of one of the attachments to the body portion of thecleanerto run the motor at a relatively low speed, said second plunger beingresponsive to the connection of another attachment to the body portionof the cleaner to run the motor at a relatively high speed, opposingside cavities in each plunger, a pin extending between each plunger andextending partially into each cavity, means in each cavity to-push thepin out of the cavity when the cavity and its plunger are depressed topush the pin deeper into the cavity of the plunger that is notdepressed, whereby only one plunger may be depressed to prevent thesimultaneous operation of both plungers.

3. In a suction cleaner having a motor, a body portion, andinterchangeable attachments for cleaning operations requiring differentmotor speeds, the improvement comprising a safety switch having firstand second switch means, said first switch means being responsive to afirst linkage means which, in turn, is responsive to the connection ofone of the attachments to the body portion of the cleaner to connect thefield windings of the motor in series to thereby run the motor at arelatively low speed, said second switch means being responsive to asecond linkage means which, in turn, is responsive to the connection ofanother attachment to the body portion of the cleaner to connect thefield windings of the motor in parallel to thereby run the motor at arelatively high speed, and means for preventing the simultaneousoperation of said first and second linkage means and, therefore, saidfirst and second switch means.

4. In a suction cleaner having a motor, a body portion, andinterchangeable attachments for cleaning operations requiring differentmotor speeds, the improvement comprising a safety switch having firstand second plungers, said first plunger being responsive to theconnection of one of the attachments to the body portion of the cleaner10 to connect the field windings of the motor in series to thereby runthe motor at a relatively low speed, said second plunger beingresponsive to the connection of another attachment to the body portionof the cleaner to connect the field windings of the motor in parallel tothereby run the motor at a relatively high speed, opposing side cavitiesin each plunger, a pin extending between each plunger and extendingpartially into each cavity, means in each cavity to push the pin out ofthe cavity when the cavity and its plunger are depressed to push the pindeeper into the cavity of the plunger that is not depressed, wherebyonly one plunger may be depressed to prevent the simultaneous operationof both plungers.

References Cited by the Examiner UNITED STATES PATENTS 2,072,696 3/1937Whitaker 15332 2,644,062 6/1953 Williams 3l8252 X 2,919,392 12/1959Smith 318252 X FOREIGN PATENTS 438,622 11/ 1935 Great Britain.

ROBERT W. MICHELL, Primary Examiner.

1. IN A SUCTION CLEANER HAVING A MOTOR, A BODY PORTION, ANDINTERCHANGEABLE ATTACHMENTS FOR CLEANING OPERATIONS REQUIRING DIFFERENTMOTOR SPEEDS, THE IMPROVEMENT COMPRISING A SAFETY SWITCH HAVING FIRSTAND SECOND SWITCH MEANS, SAID FIRST SWITCH MEANS BEING RESPONSIVE TO AFIRST LINKAGE MEANS WHICH, IN TURN, IS RESPONSIVE TO THE CONNECTION OFONE OF THE ATTACHMENTS TO THE BODY PORTION OF THE CLEANER TO RUN THEMOTOR AT A RELATIVELY LOW SPEED, SAID SECOND SWITCH MEANS BEINGRESPONSIVE TO A SECOND LINKAGE MEANS WHICH, IN TURN, IS RESPONSIVE TOTHE CONNECTION OF ANOTHER ATTACHMENT TO THE BODY PORTION OF THE CLEANERTO RUN THE MOTOR AT A RELATIVELY HIGH SPEED, AND MEANS FOR PREVENTINGTHE SIMULTANEOUS OPERATION OF SAID FIRST AND SECOND LINKAGE MEANS AND,THEREFORE, SAID FIRST AND SECOND SWITCH MEANS.